package gobot

import (
	"io"
	"time"
)

// DigitalPinOptioner is the interface to provide the possibility to change pin behavior for the next usage
type DigitalPinOptioner interface {
	// SetLabel change the pins label
	SetLabel(string) (changed bool)
	// SetDirectionOutput sets the pins direction to output with the given initial value
	SetDirectionOutput(initialState int) (changed bool)
	// SetDirectionInput sets the pins direction to input
	SetDirectionInput() (changed bool)
	// SetActiveLow initializes the pin with inverse reaction (applies on input and output).
	SetActiveLow() (changed bool)
	// SetBias initializes the pin with the given bias (applies on input and output).
	SetBias(bias int) (changed bool)
	// SetDrive initializes the output pin with the given drive option.
	SetDrive(drive int) (changed bool)
	// SetDebounce initializes the input pin with the given debounce period.
	SetDebounce(period time.Duration) (changed bool)
	// SetEventHandlerForEdge initializes the input pin for edge detection and to call the event handler on specified edge.
	// lineOffset is within the GPIO chip (needs to transformed to the pin id), timestamp is the detection time,
	// detectedEdge contains the direction of the pin changes, seqno is the sequence number for this event in the sequence
	// of events for all the lines in this line request, lseqno is the same but for this line
	SetEventHandlerForEdge(handler func(lineOffset int, timestamp time.Duration, detectedEdge string, seqno uint32,
		lseqno uint32), edge int) (changed bool)
}

// DigitalPinOptionApplier is the interface to apply options to change pin behavior immediately
type DigitalPinOptionApplier interface {
	// ApplyOptions apply all given options to the pin immediately
	ApplyOptions(...func(DigitalPinOptioner) bool) error
}

// DigitalPinner is the interface for system gpio interactions
type DigitalPinner interface {
	// Export exports the pin for use by the adaptor
	Export() error
	// Unexport releases the pin from the adaptor, so it is free for the operating system
	Unexport() error
	// Read reads the current value of the pin
	Read() (int, error)
	// Write writes to the pin
	Write(int) error
	// DigitalPinOptionApplier is the interface to change pin behavior immediately
	DigitalPinOptionApplier
}

// DigitalPinValuer is the interface to get pin behavior for the next usage. The interface is and should be rarely used.
type DigitalPinValuer interface {
	// DirectionBehavior gets the direction behavior when the pin is used the next time.
	// This means its possibly not in this direction type at the moment.
	DirectionBehavior() string
}

// DigitalPinnerProvider is the interface that an Adaptor should implement to allow clients to obtain
// access to any DigitalPin's available on that board. If the pin is initially acquired, it is an input.
// Pin direction and other options can be changed afterwards by pin.ApplyOptions() at any time.
type DigitalPinnerProvider interface {
	DigitalPin(id string) (DigitalPinner, error)
}

// PWMPinner is the interface for system PWM interactions
type PWMPinner interface {
	// Export exports the PWM pin for use by the operating system
	Export() error
	// Unexport releases the PWM pin from the operating system
	Unexport() error
	// Enabled returns the enabled state of the PWM pin
	Enabled() (bool, error)
	// SetEnabled enables/disables the PWM pin
	SetEnabled(bool) error
	// Polarity returns true if the polarity of the PWM pin is normal, otherwise false
	Polarity() (bool, error)
	// SetPolarity sets the polarity of the PWM pin to normal if called with true and to inverted if called with false
	SetPolarity(normal bool) error
	// Period returns the current PWM period in nanoseconds for pin
	Period() (uint32, error)
	// SetPeriod sets the current PWM period in nanoseconds for pin
	SetPeriod(uint32) error
	// DutyCycle returns the duty cycle in nanoseconds for the PWM pin
	DutyCycle() (uint32, error)
	// SetDutyCycle writes the duty cycle in nanoseconds to the PWM pin
	SetDutyCycle(uint32) error
}

// PWMPinnerProvider is the interface that an Adaptor should implement to allow
// clients to obtain access to any PWMPin's available on that board.
type PWMPinnerProvider interface {
	PWMPin(id string) (PWMPinner, error)
}

// I2cSystemDevicer is the interface to a i2c bus at system level, according to I2C/SMBus specification.
// Some functions are not in the interface yet:
// * Process Call (WriteWordDataReadWordData)
// * Block Write - Block Read (WriteBlockDataReadBlockData)
// * Host Notify - WriteWordData() can be used instead
//
// see: https://docs.kernel.org/i2c/smbus-protocol.html#key-to-symbols
//
// S: Start condition; Sr: Repeated start condition, used to switch from write to read mode.
// P: Stop condition; Rd/Wr (1 bit): Read/Write bit. Rd equals 1, Wr equals 0.
// A, NA (1 bit): Acknowledge (ACK) and Not Acknowledge (NACK) bit
// Addr (7 bits): I2C 7 bit address. (10 bit I2C address not yet supported by gobot).
// Comm (8 bits): Command byte, a data byte which often selects a register on the device.
// Data (8 bits): A plain data byte. DataLow and DataHigh represent the low and high byte of a 16 bit word.
// Count (8 bits): A data byte containing the length of a block operation.
// [..]: Data sent by I2C device, as opposed to data sent by the host adapter.
type I2cSystemDevicer interface {
	// ReadByte must be implemented as the sequence:
	// "S Addr Rd [A] [Data] NA P"
	ReadByte(address int) (byte, error)

	// ReadByteData must be implemented as the sequence:
	// "S Addr Wr [A] Comm [A] Sr Addr Rd [A] [Data] NA P"
	ReadByteData(address int, reg uint8) (uint8, error)

	// ReadWordData must be implemented as the sequence:
	// "S Addr Wr [A] Comm [A] Sr Addr Rd [A] [DataLow] A [DataHigh] NA P"
	ReadWordData(address int, reg uint8) (uint16, error)

	// ReadBlockData must be implemented as the sequence:
	// "S Addr Wr [A] Comm [A] Sr Addr Rd [A] [Count] A [Data] A [Data] A ... A [Data] NA P"
	ReadBlockData(address int, reg uint8, data []byte) error

	// WriteByte must be implemented as the sequence:
	// "S Addr Wr [A] Data [A] P"
	WriteByte(address int, val byte) error

	// WriteByteData must be implemented as the sequence:
	// "S Addr Wr [A] Comm [A] Data [A] P"
	WriteByteData(address int, reg uint8, val uint8) error

	// WriteBlockData must be implemented as the sequence:
	// "S Addr Wr [A] Comm [A] Count [A] Data [A] Data [A] ... [A] Data [A] P"
	WriteBlockData(address int, reg uint8, data []byte) error

	// WriteWordData must be implemented as the sequence:
	// "S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] P"
	WriteWordData(address int, reg uint8, val uint16) error

	// WriteBytes writes the given data starting from the current register of bus device.
	WriteBytes(address int, data []byte) error

	// Read implements direct read operations.
	Read(address int, b []byte) (int, error)

	// Write implements direct write operations.
	Write(address int, b []byte) (n int, err error)

	// Close closes the character device file.
	Close() error
}

// SpiSystemDevicer is the interface to a SPI bus at system level.
type SpiSystemDevicer interface {
	TxRx(tx []byte, rx []byte) error
	// Close the SPI connection.
	Close() error
}

// BusOperations are functions provided by a bus device, e.g. SPI, i2c.
type BusOperations interface {
	// ReadByteData reads a byte from the given register of bus device.
	ReadByteData(reg uint8) (uint8, error)
	// ReadBlockData fills the given buffer with reads starting from the given register of bus device.
	ReadBlockData(reg uint8, data []byte) error
	// WriteByteData writes the given byte value to the given register of bus device.
	WriteByteData(reg uint8, val uint8) error
	// WriteBlockData writes the given data starting from the given register of bus device.
	WriteBlockData(reg uint8, data []byte) error
	// WriteByte writes the given byte value to the current register of bus device.
	WriteByte(val byte) error
	// WriteBytes writes the given data starting from the current register of bus device.
	WriteBytes(data []byte) error
}

// I2cOperations represents the i2c methods according to I2C/SMBus specification.
type I2cOperations interface {
	io.ReadWriteCloser
	BusOperations
	// ReadByte reads a byte from the current register of an i2c device.
	ReadByte() (byte, error)
	// ReadWordData reads a 16 bit value starting from the given register of an i2c device.
	ReadWordData(reg uint8) (uint16, error)
	// WriteWordData writes the given 16 bit value starting from the given register of an i2c device.
	WriteWordData(reg uint8, val uint16) error
}

// SpiOperations are the wrappers around the actual functions used by the SPI device interface
type SpiOperations interface {
	BusOperations
	// ReadCommandData uses the SPI device TX to send/receive data.
	ReadCommandData(command []byte, data []byte) error
	// Close the connection.
	Close() error
}

// Adaptor is the interface that describes an adaptor in gobot
type Adaptor interface {
	// Name returns the label for the Adaptor
	Name() string
	// SetName sets the label for the Adaptor
	SetName(string)
	// Connect initiates the Adaptor
	Connect() error
	// Finalize terminates the Adaptor
	Finalize() error
}

// Porter is the interface that describes an adaptor's port
type Porter interface {
	Port() string
}